41-year-old Assange has been holed up inside the building since his asylum claim in June last year. He will pass the first anniversary of being holed up in the Ecuadorean embassy this week in an effort to avoid extradition to Sweden where he is under investigation for alleged sex offences.
A meeting between UK foreign secretary William Hague and his Ecuadorian counterpart, Ricardo Patino here failed to break the deadlock over Assange, an Australian national.
"Ministers agreed that officials should establish a working group to find a diplomatic solution to the issue of Julian Assange, but no substantive progress was made," he said.
"The Foreign Secretary was clear once again that any resolution would need to be within the laws of the United Kingdom," he added.
More From This Section
Britain has refused to grant the former computer hacker safe passage out of the Ecuadorian embassy.
According to a report in the 'Independent' newspaper, Assange believes that staying at the embassy in London is preferable to facing the US legal system.
He believes the claims are a ruse so he can eventually be sent to the US for trial over the leaking of formerly secret US cables. The authorities have denied this.
Patino made it clear that Assange would not be smuggled out of the embassy, saying he should be allowed to leave and go to Ecuador. He said it was "grossly unjust" that Assange could not leave the embassy without being arrested.